#include <stdio.h>
int main()
{
    float x, y;
    printf("please enter x= ");
    scanf("%f", &x);
    if (x < 0)
        y = x + 20;
    else if (x<10)
        y = x * x;
    else
    y = 3 * x - 3;
        printf("y=%6.2f", y);

    return 0;
}